Research On Structural Drag Reduction Design Of Subsoiler And Wear Resistance Of Surface Laser Fusion Coating

As an important conservation tillage technology,Subsoiling is widely used in agricultural production.Subsoiling is subjected to resistance and friction wear from soil and plant roots and stems during deep loosening operations,resulting in increased traction energy consumption and subsoiler wear,affecting the efficiency and quality of deep loosening operations,and causing huge economic losses.Therefore,the problem of reducing the resistance and improving the wear resistance of subsoiling operation is an urgent problem to be solved.This study aimed to design an optimized deep pine shovel through the construction of a subsoiler contact model to analyze the force conditions on the shovel in the soil,followed by structural resistance reduction design.Additionally,a wear-resistant ceramic coating was prepared on the shovel tip surface using a laser melting process to achieve the goals of resistance reduction and wear-resistant strengthening.The main research findings are summarized as follows:（1）Construction of subsoiler contact model.The study involved experimental measurements of characteristic parameters such as soil texture,density,moisture content,and internal friction angle,along with the construction of a soil groove discrete element model and deep pine shovel-soil contact model.The simulation results revealed that a resistance reduction effect of 27.53%can be achieved with a deep pine depth of 250 mm,based on parameters such as soil entry angle of 23°and deep pine speed of 0.83 m/s.Accordingly,a double-pronged Subsoiler with a back tilt angle of 5°was designed to ensure minimal soil disturbance and optimal soil breaking effect.（2）Preparation of ni-based Al₂O₃+Si C wear-resistant coating by laser fusion coating.A ni-based Al₂O₃+Si C wear-resistant coating was prepared on the subsoiler surface using laser melting,with 65 Mn steel（the material of the deep loosening shovel）as the melting substrate,Ni62 as the self-fusing alloy powder,and Al₂O₃and Si C as the reinforcing phase ceramic powder.The study analyzed the microhardness of the coating section,distribution of macroscopic cracks on the surface,and element diffusion at the melting interface to investigate the impact of melting process and coating material parameters on coating quality.The optimal process parameters were determined as 1400 W laser power,10 mm/s laser scanning speed,1.1 mm powder thickness,and 4 wt%ceramic phase contents.（3）Improvement of coating quality with Ce O₂.To address the issue of cracks in the melt coating,the causes of macroscopic cracks were analyzed,and the inhibitory effect of Ce O₂addition on coating cracks was investigated.The study found that the addition of 0.5wt%Ce O₂promotes the diffusion of the hard phase in the composite coating,resulting in significantly smaller grain size in the melt zone,more homogeneous distribution of elements in the melt zone,and a 22.76%increase in microhardness of the coating.（4）Frictional wear test and soil groove resistance reduction test.After incorporating0.5 wt%Ce O₂into the Ni-based Al₂O₃+Si C composite coating,frictional wear and soil groove resistance reduction tests were conducted.The results showed that the wear resistance of the composite coating improved by 440%,with minimized friction coefficient,and the main form of wear being adhesive and abrasive wear alternately.The error between the simulation and test results of deep pine shovel on soil disturbance was within 17%,indicating high accuracy.The test results show that the mass wear rate of the cladding coating sample is only 25%of that of the unclad coating tip...